Biology subjects

Stabler, C. L.

Publications and source records attributed to Stabler, C. L..

4 recordsLinked to original sources

bioRxiv2026

Optimizing 3D-printed Scaffold Geometry Decreases Foreign Body Response and Enhances Allogeneic Islet Transplant Outcomes

Cellular therapy, such as beta cell transplantation for Type 1 diabetes, is a promising approach to durably alleviate disease states. Implanting cells within porous scaffolds is beneficial as they distribute the cells and mechanically support implantation; however, scaffolds can exacerbate foreign body responses (FBR). While the geometric features of a scaffold are known to impact FBR, there is limited consensus on what makes an ideal implant. Some have explored the role of pore size and interconnectivity; however, the impact of rung thickness between pores on FBR is broadly understudied. To investigate this parameter, we created a scaffold with reproducible geometric features and high biostability by combining 3D-printing with the polymer polydimethylsiloxane (PDMS). We tested 3D-printed scaffold prototypes with identical pore sizes but distinct PDMS rung thicknesses ranging from 150 to 300 {micro}m. Upon transplantation, biocompatibility screening in a mouse model revealed that scaffolds with thicker PDMS rungs led to increased intra-device fibrosis. Additional spatio-proteomic analysis revealed distinct differences in host responses to rung changes, with alterations in macrophage and adaptive immune cell markers, as well as fibrotic proteins, within scaffolds containing thicker rungs. Selecting the optimized rung size, we evaluated its efficacy in rat syngeneic and allogeneic islet transplant models. In the allogeneic model, 3D-printed scaffold islet implants demonstrated robust efficacy and stability, yielding improved outcomes compared to PDMS scaffolds without optimized geometric features. Results from this study reveal how specific geometric scaffold features critically influence FBR to biomaterial implants, accelerating or mitigating fibrotic responses, and ultimately determining transplant success.

bioengineering↗

bioRxiv2025

Efficient transduction of pancreas tissue slices with genetically encoded calcium integrators

This study combines live pancreas tissue slices with viral transduction of the Calcium Modulated Photoactivatable Ratiometric Integrator 2 (CaMPARI2) biosensor for high-throughput analysis of islet calcium secretagogue responses. A key challenge of the pancreas slice model has been efficient transgene delivery throughout the slice volume while maintaining viability and function. Here, we demonstrate a robust adenoviral gene delivery approach to transduce slices with CaMPARI2 and apply photoconverting light to permanently mark glucose-induced calcium activity across all islets. This approach demonstrates glucose responsive CaMPARI2 labeling that correlates with insulin secretion. Using this novel high-throughput approach, we examine the relationship between islet size and calcium response. Larger isolated islets exhibit greater CaMPARI2 photoconversion in high glucose, whereas no size-function correlation is observed in islets resident in live slices. We also observe that slices capture a substantially higher proportion of small islets than isolated islets. Integrating CaMPARI2 with live pancreas slice studies enables multiplexed analyses, linking functional readouts to spatial features.

physiology↗

bioRxiv2020

Controlled Release of Anti-inflammatory and Pro-angiogenic Factors from Macroporous Scaffolds

The simultaneous local delivery of anti-inflammatory and pro-angiogenic agents via biomaterial scaffolds presents a promising method for improving the engraftment of tissue-engineered implants while avoiding potentially detrimental systemic delivery. In this study, PDMS microbeads were loaded with either anti-inflammatory dexamethasone (Dex) or pro-angiogenic 17{beta}-estradiol (E2) and subsequently integrated into a single macroporous scaffold to create a controlled, dual drug-delivery platform. Compared to a standard monolithic drug dispersion scaffold, macroporous scaffolds containing drug-loaded microbeads exhibited reduced initial burst release and increased the durability of drug release for both agents. Incubation of scaffolds with LPS-stimulated M1 macrophages found that Dex suppressed the production of pro-inflammatory and pro-angiogenic factors, when compared to drug-free control scaffolds; however, the co-incubation of macrophages with Dex and E2 scaffolds restored their pro-angiogenic features. Following implantation, Dex-loaded microbead scaffolds (Dex-{micro}BS) suppressed host cell infiltration and integration, when compared to controls. In contrast, the co-delivery of dexamethasone with estrogen from the microbead scaffold (Dex/E2-{micro}BS) dampened overall host cell infiltration but restored graft vascularization. These results demonstrate the utility of a microbead scaffold approach for the controlled, tailored, and local release of multiple drugs from an open framework implant. It further highlights the complementary impacts of local Dex and E2 delivery to direct the healthy integration of implants, which has broad applications to the field of tissue engineering and regenerative medicine.

bioengineering↗

bioRxiv2019

In Vitro Platform Establishes Antigen-Specific CD8+ T Cell Cytotoxicity to Encapsulated Cells via Indirect Antigen Recognition

Cell replacement therapy has the potential to cure diseases caused by the absence or malfunction of specialized cells. A substantial impediment to the success of any non-autologous cellular transplant is the need for systemic immunosuppressive drugs to prevent host-mediated rejection of the foreign cells. Cellular encapsulation, i.e., the entrapment of cells within stable polymeric hydrogels, has been clinically explored to prevent host immune recognition and attack, but the efficacy of these encapsulated grafts is poor. While several studies have explored improvements in innate immune acceptance of these encapsulated cells, little attention has been paid to the roles of adaptive immune responses, specifically graft-targeting T cell activation, in graft destabilization. Herein, we established an efficient, single-antigen in vitro platform capable of delineating direct and indirect host T cell recognition to microencapsulated cellular grafts and evaluating their consequential impacts. Using alginate as the model hydrogel, encapsulated membrane-bound ovalbumin (mOVA) stimulator cells were incubated with antigen-specific OTI lymphocytes and subsequent OVA-specific CD8+ T cell activation and effector function were quantified. We established that alginate microencapsulation abrogates direct T cell activation by interrupting donor-host interaction; however, indirect T cell activation mediated by host antigen presenting cells (APCs) primed with shed donor antigens still occurs. These activated T cells imparted cytotoxicity on the encapsulated cells, likely via diffusion of cytotoxic solutes. Overall, this platform delivers unique mechanistic insight into the impacts of hydrogel encapsulation on host adaptive immune responses, as well as a tool for the efficient immune screening on new encapsulation methods and/or synergistic immunomodulatory agents.

bioengineering↗